Extended depth-of-focus by digital holographic microscopy

摘要

A recurrent problem in microscopy is the finite depth-of-focus linked to the NA of microscope objectives. Digitalnholographic microscopy (DHM) has the unique feature of being able to numerically change the focus from a singlenhologram without the need of moving the sample. Extended depth of focus of amplitude images has been demon-nstrated, but it hasmarginal interest for themetrological application of DHMthat needs the topography. In this Letter,nwe demonstrate that DHM is able to provide not only extended depth-of-focus amplitude images but extended fo-ncused complex data from which the topography is computed. For this purpose, reflection and transmission mea-nsurements on micro-optics (microlens and retroreflector) performed by using standard reconstruction or thenextended focused complex data are compared. These experiments demonstrate that DHM measures, from a singlenhologram acquisition, the accurate sample topography on a numerically increased depth-of-focus. © 2010 OpticalnSociety of America